An Interesting Observation Regarding the Sine Curve

1968 ◽  
Vol 61 (4) ◽  
pp. 391-392
Author(s):  
David Paisley
Keyword(s):  
Cylindrical Shape ◽  
Interesting Observation ◽  
Sine Curve

I was having some difficulty with a transparency (Fig. 1) that I had made for my trigonometry class. The transparency had a tendency to curl and roll into a cylindrical shape. I then noticed that if the cylinder were twisted to a particular size, the sine curve wrapped around the cylinder in a shape that resembled an ellipse (Fig. 2). To obtain this particular size, the cylinder was twisted so that the points labeled K matched, and the points labeled O matched. The sine curve wrapped around the cylinder about three times on the particular model I had.

Effect of pipe expansion on the redistribution of residual stresses after molding

2020 ◽  
Vol 10 (2) ◽  
pp. 122-126
Author(s):  
Nikolay A. Makhutov ◽  
◽  
Dmitry A. Neganov ◽  
Eugeny P. Studenov ◽  
◽  
...  
Keyword(s):  
Residual Stresses ◽  
Strain Distribution ◽  
Strain State ◽  
Stress And Strain ◽  
Cylindrical Shape ◽  
Pipe Material ◽  
Pipe Expansion ◽  
Calculation Results ◽  
Residual Deformations ◽  
Stress And Strain Distribution

In the factory, pipes for trunk oil and oil product pipelines are obtained by molding and welding. To ensure a cylindrical shape and reduce technological residual stresses, expansion technology is used. Pipe expansion causes a significant change in the values of residual deformations and stresses. The article presents both the calculation results and graphs regarding stress and strain distribution during bending of the stock and their redistribution after expansion. Based on the calculation results, the final total values of residual stresses and residual deformations caused by bending and expansion were stated to be important components of the stress-strain state observed in pipelines being operated under cyclic loading, as well as those used in assessing how degradation affects the ductility of the pipe material. These factors were concluded as being reasonably taken into account when performing verification calculations regarding long-running pipelines if, based on their diagnostics and analysis, their state does not meet modern strength requirements.

Redrawing Operation a Star Shape from Cylindrical Shape Using Experimental and FE Analysis

2020 ◽  
Vol 38 (1A) ◽  
pp. 25-32
Author(s):  
Waleed Kh. Jawad ◽  
Ali T. Ikal
Keyword(s):  
Finite Element ◽  
Effective Strain ◽  
Element Model ◽  
Cylindrical Shape ◽  
Element Analysis ◽  
Punch Force ◽  
Maximum Value ◽  
Element Simulation ◽  
Blank Sheet ◽  
The Finite Element Model

The aim of this paper is to design and fabricate a star die and a cylindrical die to produce a star shape by redrawing the cylindrical shape and comparing it to the conventional method of producing a star cup drawn from the circular blank sheet using experimental (EXP) and finite element simulation (FES). The redrawing and drawing process was done to produce a star cup with the dimension of (41.5 × 34.69mm), and (30 mm). The finite element model is performed via mechanical APDL ANSYS18.0 to modulate the redrawing and drawing operation. The results of finite element analysis were compared with the experimental results and it is found that the maximum punch force (39.12KN) recorded with the production of a star shape drawn from the circular blank sheet when comparing the punch force (32.33 KN) recorded when redrawing the cylindrical shape into a star shape. This is due to the exposure of the cup produced drawn from the blank to the highest tensile stress. The highest value of the effective stress (709MPa) and effective strain (0.751) recorded with the star shape drawn from a circular blank sheet. The maximum value of lamination (8.707%) is recorded at the cup curling (the concave area) with the first method compared to the maximum value of lamination (5.822%) recorded at the cup curling (the concave area) with the second method because of this exposure to the highest concentration of stresses. The best distribution of thickness, strains, and stresses when producing a star shape by

scholarly journals Interaction of the combustion front of methane-air mixture at low pressures with obstacles of cylindrical shape

FirePhysChem ◽  
2021 ◽  
Author(s):  
Nickolai M. Rubtsov ◽  
Victor I. Chernysh ◽  
Georgii I. Tsvetkov ◽  
Kirill Ya. Troshin
Keyword(s):  
Combustion Front ◽  
Cylindrical Shape ◽  
Low Pressures

scholarly journals Tailoring Atomoxetine Release Rate from DLP 3D-Printed Tablets Using Artificial Neural Networks: Influence of Tablet Thickness and Drug Loading

Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 111
Author(s):  
Gordana Stanojević ◽  
Djordje Medarević ◽  
Ivana Adamov ◽  
Nikola Pešić ◽  
Jovana Kovačević ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Release Rate ◽  
Drug Loading ◽  
Prolonged Release ◽  
Cylindrical Shape ◽  
Poly Ethylene Glycol ◽  
Scanning Calorimetry ◽  
3D Printed ◽  
Artificial Neural ◽  
Poly Ethylene

Various three-dimensional printing (3DP) technologies have been investigated so far in relation to their potential to produce customizable medicines and medical devices. The aim of this study was to examine the possibility of tailoring drug release rates from immediate to prolonged release by varying the tablet thickness and the drug loading, as well as to develop artificial neural network (ANN) predictive models for atomoxetine (ATH) release rate from DLP 3D-printed tablets. Photoreactive mixtures were comprised of poly(ethylene glycol) diacrylate (PEGDA) and poly(ethylene glycol) 400 in a constant ratio of 3:1, water, photoinitiator and ATH as a model drug whose content was varied from 5% to 20% (w/w). Designed 3D models of cylindrical shape tablets were of constant diameter, but different thickness. A series of tablets with doses ranging from 2.06 mg to 37.48 mg, exhibiting immediate- and modified-release profiles were successfully fabricated, confirming the potential of this technology in manufacturing dosage forms on demand, with the possibility to adjust the dose and release behavior by varying drug loading and dimensions of tablets. DSC (differential scanning calorimetry), XRPD (X-ray powder diffraction) and microscopic analysis showed that ATH remained in a crystalline form in tablets, while FTIR spectroscopy confirmed that no interactions occurred between ATH and polymers.

scholarly journals Data-Driven Study on the Sustainable Log Movements: Impact of Rail Car Fleet Size on Freight Storage and Car Idling

2020 ◽  
Vol 12 (11) ◽  
pp. 4563
Author(s):  
Sangpil Ko ◽  
Pasi Lautala ◽  
Kuilin Zhang
Keyword(s):  
Service Life ◽  
Seasonal Dynamics ◽  
Lake Superior ◽  
Data Driven ◽  
Short Term ◽  
Fleet Size ◽  
Interesting Observation ◽  
The Us ◽  
Term Storage ◽  
Scale Data

Rail car availability and the challenges associated with the seasonal dynamics of log movements have received growing attentions in the Lake Superior region of the US, as a portion of rail car fleet is close to reaching the end of its service life. This paper proposes a data-driven study on the rail car peaking issue to explore the fleet of rail cars dedicated to being used for log movements in the region, and to evaluate how the number of cars affects both the storage need at the sidings and the time the cars are idled. This study is based on the actual log scale data collected from a group of forest companies in cooperation with the Lake State Shippers Association (LSSA). The results of our analysis revealed that moving the current log volumes in the region would require approximately 400–600 dedicated and shared log cars in ideal conditions, depending on the specific month. While the higher fleet size could move the logs as they arrive to the siding, the lower end would nearly eliminate the idling of rail cars and enable stable volumes throughout the year. However, this would require short-term storage and additional handling of logs at the siding, both elements that increase the costs for shippers. Another interesting observation was the fact that the reduction of a single day in the loading/unloading process (2.5 to 1.5 days) would eliminate almost 100 cars (20%) of the fleet without reduction in throughput.

Oospore dimensions and wall ornamentation in Chara braunii

Biologia ◽  
2008 ◽  
Vol 63 (4) ◽  
Author(s):  
Patrycja Boszke ◽  
Mariusz Pełechaty ◽  
Andrzej Pukacz
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Local Population ◽  
Polar Axis ◽  
Morphological Features ◽  
Cylindrical Shape ◽  
Reproductive Structures ◽  
Equatorial Diameter ◽  
Variable Character ◽  
Scanning Electron

AbstractMorphological features of oospores of a rarely noted species Chara braunii Gmel. were examined in a local population (fishpond near Tuplice village, Ziemia Lubuska region, mid-western Poland). The largest polar axis (LPA, length), largest equatorial diameter (LED, width), isopolarity index (ISI = LPA/LED* 100), and the number of ridges and width of fossa of 90 oospores were measured. Additionally, the oospore wall ornamentation pattern was examined by means of scanning electron microscopy (SEM). As a result, a cylindrical shape and the lack of so-called “shoulder” were found. Oospore length and width ranged between 466.8–600.1 µm and 250.1–366.7 µm, respectively, with the ISI index values between 148 and 213. The number of ridges was 8–10 and the width of fossa varied between 50.0 and 66.7 µm. The oospore width appeared to be the most changeable feature, whereas, by contrast, the number of ridges was the least variable character. Wall ornamentation can be described as tuberculate and a ribbon was present on the ridges. As a comparative material for the study performed, 9 oospores from Professor Izabela Dąmbska’s Collection of Charophytes of Poland were measured. It was evidenced that variation ranges of most of the features of Chara braunii oospores from Tuplice fishpond are similar to those of Professor Dąmbska’s herbarium materials and to data reported by authors from other countries as well. The morphology of reproductive structures does not follow the variation of thalli characteristics.

Design and Construction of Cervix Phantom for Brachytherapy Dose Assessment Procedure for Clinical Application

2017 ◽  
pp. 106-109
Author(s):  
Justice Avevor ◽  
Issahaku Shirazu ◽  
Samuel Nii Adu Tagoe ◽  
J. H. Amuasi ◽  
J. J. Fletcher
Keyword(s):  
Clinical Application ◽  
Excellent Result ◽  
Dose Assessment ◽  
Internal Diameter ◽  
Cylindrical Shape ◽  
Assessment Procedure ◽  
External Diameter ◽  
Actual Patient ◽  
Average Patient ◽  
Patient Size

An important point to consider in a brachytherapy dosimetry study is the design of an appropriate phantom size in calculations or experimental measurements. Perspex sheets of various size and thickness are used to design the cervix phantom. The aim of the study is to design and construct cervix phantom to mimic the pelvic segment of a standard adult human patients undergoing Brachytherapy. This is to allow assessment of dose to cervix and the surrounding tissues during cervix Brachytherapy. The methodology include; first phantom design where physical dimensions of the phantom were determined from a sampling of 30 patients’ cases to simulate an average patient size. Secondly, construction of phantom with fabricated cylindrical shape, composed of 6 mm Perspex sheets, and the assembly enclosed with the 4 mm Perspex sheet. The result of the constructed phantom had lateral separation of 34 cm, an anterior and posterior separation of 27 cm; with length of 33 cm. The Perspex pieces were glued to each other with Trichloromethane (chloroform) at room temperature. Chloroform dissolves the Perspex (PMMA), and when applied to the surfaces of the Perspex sheets, the surfaces stick together after the chloroform dries up. In forming the surface of the phantom, the 4 mm Perspex sheet was oven heated to a temperature of 140?C to make the sheet malleable. One end of the phantom was made thicker than the other end by gluing another 6 mm Perspex sheet such that the thickness of that particular end of the phantom was 12 mm. A hole of diameter 6.5 cm, which was a little bit posterior to the phantom, was created central to the 12 mm end of the phantom. The opening created was covered by 11 x 11 cm2 and 12 mm Perspex slab which was formed by gluing two 6 mm sheets together. A hole of diameter 5 cm was also made central to the cover created, such that the centre of this hole matches that of the hole on the end of the phantom. A 2.4 cm thick ring with internal diameter of 5 cm and external diameter of 6 cm was fabricated from 2.4 cm Perspex slab, which was formed from gluing four pieces of 6 mm Perspex sheets together. The fabricated ring was mounted on the 11 x 11 cm2 cover created such that the internal walls of the ring and that of the hole in the cover matches. The ring was then glued to the cover using the chloroform. The built phantom simulate actual patient anatomy and produce an excellent result to be use for clinical application.

Influence of Various Basin Types on Performance of Passive Solar Still: A Review

2021 ◽  
Vol 10 (4) ◽  
pp. 789-802
Author(s):  
Tri Hieu Le ◽  
Minh Tuan Pham ◽  
H Hadiyanto ◽  
Van Viet Pham ◽  
Anh Tuan Hoang
Keyword(s):  
Water Depth ◽  
Thermal Efficiency ◽  
Tracking System ◽  
Design Parameters ◽  
Cylindrical Shape ◽  
Solar Still ◽  
Practical Utilization ◽  
Passive Solar Still ◽  
Passive Solar ◽  
The Impact

Passive solar still is the simplest design for distilling seawater by harnessing solar energy. Although it is undeniable that solar still is a promising device to provide an additional freshwater source for global increasing water demand, low thermal efficiency along with daily distillate yield are its major disadvantages. A conventional solar still can produced 2 to 5 L/m2day. Various studies have been carried out to improve passive solar stills in terms of daily productivity, thermal efficiency, and economic effectiveness. Most of the researches that relate to the daily output improvement of passive solar still concentrates on enhancing evaporation or/and condensation processes. While the condensation process is influenced by wind velocity and characteristics of the condensed surface, the evaporation process is mainly affected by the temperature of basin water. Different parameters affect the brackish water temperature such as solar radiation, design parameters (for example water depth, insulators, basin liner absorptivity, reflectors, sun tracking system, etc). The inclined angle of the top cover is suggested to equal the latitude of the experimental place. Moreover, the decrease of water depth was obtained as a good operational parameter, however, the shallow water depth is required additional feed water for ensuring no dry spot existence. Reflectors and sun-tracking systems help solar still absorb as much solar intensity as possible. The internal reflector can enhance daily yield and efficiency of stepped solar still up to 75% and 56% respectively, whereas, passive solar still with the support of a sun-tracking system improved daily yield up to 22%. Despite large efforts to investigate the impact of the different parameters on passive solar distillation, the effect of the basin liner (including appropriate shapes and type of material), needs to be analyzed for improvement in practical utilization. The present work has reviewed the investigation of the solar still performance with various types of basin liner. The review of solar stills has been conducted critically with rectangular basin, fins basin, corrugated basin, wick type, steps shape, and cylindrical shape basin with variety of top cover shapes. The findings from this work conclude that the basin liner with a cylindrical shape had better performance in comparison with other metal types and provides higher freshwater output. Stepped type, inclined, fin absorber, and corrugated shapes had the efficient performance.  Further exploration revealed that copper is the best-used material for the productivity of passive solar still.

Improvement of Method and Mechanism for Conical and Paraboloid Springs Hardening

2021 ◽  
Vol 1037 ◽  
pp. 227-232
Author(s):  
Nikita A. Zemlyanushnov ◽  
Nadezhda Y. Zemlyanushnova
Keyword(s):  
New Method ◽  
Cylindrical Shape ◽  
Plastic Deformations ◽  
Conical Shape ◽  
Inner Surface ◽  
Hardening Mechanisms ◽  
The Difference ◽  
Compression Springs

The disadvantage of the known methods of hardening springs is the impossibility of their use when hardening springs of a conical shape or of a shape of a paraboloid of rotation, since they are intended only for cylindrical shape springs and are not suitable for conical shape springs or those of a shape of a paraboloid of rotation specifically because of the difference in the shape of the springs. One of the disadvantages of the known springs hardening mechanisms is the impossibility of hardening the inner surface of the conical compression springs. A new method of hardening springs is proposed, the unmatched advantage of which is the ability to create plastic deformations on the inner and outer surfaces of the spring coils compressed to contact and on the surfaces along the line of contact between the coils. A new advantageous mechanism for hardening springs is proposed, which makes it possible to harden the inner surface of compression springs having a conical shape or a paraboloid shape of rotation, in a compressed state.

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